Publication Date

1974

Document Type

Dissertation/Thesis

First Advisor

Vaughn, Joseph W.

Degree Name

M.S. (Master of Science)

Department

Department of Chemistry

LCSH

Organochromium compounds

Abstract

A new synthetic method for the preparation of difluoro(triethylenetetramine)chromium(III) iodide is reported. The complex was prepared by a ligand substitution reaction starting with trans-difluorobis(1,3-propanediamine) chromium(III) iodide and excess triethylenetetramine, (trien). Solvents for the reaction were either 95% ethanol or 2-methoxyethanol. The product was assigned the cis-α-configuration on the basis of its color, solubility, ultraviolet-visible spectrum, infrared spectrum, optical activity, and molar conductance measurements. Derivatives of cis-α-[Cr(trien)F₂]I were also prepared and characterized. The diaquo (triethylenetetramine)chromium(III) percholrate complex, previously unreported in the solid state, was synthesized by allowing [Cr(trien)F₂]⁺ to aquate completely in concentrated perchloric acid. The complex was isolated by crystallization from cold aqueous solution. In concentrated hydrobromic acid the aquation of the first flouride ligand of [Cr(trien)F₂]⁺ yielded the complex fluoroaquo(triethylenetetramine)chromium(III) bromide, which could be precipitated from the reaction mixture by the addition of ethanol. Reaction of [Cr(trien)F₂]⁺I with concentrated hydrochloric acid at low temperature produced dichloro(triethylenetetramine)-chromium(III) iodide. The iodide salt of this cation was also obtained from the previously reported cis-α-[Cr(trien)Cl₂]Cl·H₂O by rapid metathesis with sodium iodide. Adibromo-trien species, which may be the new binulclear complex [Cr₂(trien)₂Br₂]Br₃, was synthesized by treating [Cr(trien)F₂]I with cold hydrombromic acid. Replacement of the fluoro ligands by bromide ions proceeded slowly and with concurrent dimerization. Another previously unreported dibromo species, dibro(triethylenetetramine)chromium(III) bromide di(mercury(II)bromide) dihydrate, was obtained by treatment of the corresponding difluoro complex with mercury(II)bromide in hydrobromic acid.Unequivocal assignment of configuration was not possible for this complex. All other complexes were shown to have a cis-α geometry by comparison of their unltraviolet-visible and infrared spectra with those of know cis-α complexes. These results indicate that cis-α-[Cr(trien)F₂]I undergoes subsition of the non-chelating ligands with retention of configuration.

Comments

Includes bibliographical references.||Includes illustrations.

Extent

47 pages

Language

eng

Publisher

Northern Illinois University

Rights Statement

In Copyright

Rights Statement 2

NIU theses are protected by copyright. They may be viewed from Huskie Commons for any purpose, but reproduction or distribution in any format is prohibited without the written permission of the authors.

Media Type

Text

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